Fix for PDFs with lots of named destinations take a long time to load.

chrome/browser/resources/pdf/navigator.js

Index: chrome/browser/resources/pdf/navigator.js
diff --git a/chrome/browser/resources/pdf/navigator.js b/chrome/browser/resources/pdf/navigator.js
index 57c15d4d26c47c983f83a839c766cb79d22f9dfe..765f15589244d7147812e31c3ccbf0f157a01b47 100644
--- a/chrome/browser/resources/pdf/navigator.js
+++ b/chrome/browser/resources/pdf/navigator.js
@@ -74,12 +74,22 @@ Navigator.prototype = {
     if (newTab) {
       this.navigateInNewTabCallback_(url);
     } else {
-      var pageNumber =
-          this.paramsParser_.getViewportFromUrlParams(url).page;
-      if (pageNumber != undefined)
-        this.viewport_.goToPage(pageNumber);
-      else
-        this.navigateInCurrentTabCallback_(url);
+      this.paramsParser_.getViewportFromUrlParams(
+          url, this.onViewportReceived_.bind(this));
     }
+  },
+
+   /**
+   * @private
+   * Called when the viewport position is received.
+   * param {Object} viewportPosition Dictionary containing the viewport
+   *     position.
+   */
+  onViewportReceived_: function(viewportPosition) {
+    var pageNumber = viewportPosition.page;
+    if (pageNumber != undefined)
+      this.viewport_.goToPage(pageNumber);
+    else
+      this.navigateInCurrentTabCallback_(url);
   }
 };